There is an increased awareness among the agricultural community as to the economic importance of planting accuracy. This increased awareness and the desire to improve seed meter accuracy is due in part to the recent increase in the price of corn. For example, with corn prices near $4 per bushel, improving the seed singulation accuracy of a seed meter by a single percentage point can translate into eight dollars ($8.00) more per acre. Accordingly, there is a significant need to provide a seed meter that will consistently produce seed singulation accuracies of 98% or above.
With respect to vacuum type seed meters, a number of factors can affect seed singulation accuracies. One such factor is the treatment applied to the seeds. The seed corn industry is applying new formulations and heavier treatments to the seed to protect the seed from new pests and other insects and disease, but which are also more environmentally friendly. These new treatments can make the seed surface rough, thereby affecting entrainment over the apertures of vacuum disks. Additionally, some of these new treatments can become sticky, requiring more aggressive agitation of the seeds within the seed pool of the meters in order to keep the seeds from sticking together.
One type of vacuum meter that has experienced commercial success in recent years is the John Deere Pro-Series™ Meter found on Deere's central-fill or bulk-fill planters such as disclosed in U.S. Pat. Nos. 6,581,533 and 6,935,255 both of which are incorporated herein by reference. While the Pro-Series™ Meter may serve its intended purpose certain factors can effect its performance.
For example, as previously identified, certain heavily coated seed treatments may cause the seed within the seed pool to stick together reducing the flowability of the seed. Thus, unless the seed is aggressively agitated by the seed disk as it rotates through the seed pool, the reduced flowability may result in poor loading of the seed onto the apertures of the seed disk, which translate into seek skips in the furrow. Deere's standard seed disks for the Pro-Series™ Meter do not provide very aggressive agitation. As a result, under some conditions when using Deere's standard disks, the performance or accuracy of the seed meter can be less than desirable.
In order to overcome this problem, farmers have attempted to replace Deere's standard seed disks with after-market disks that have larger or deeper ribs or fins to provide more aggressive agitation of the seeds. While these deeper ribs provide more aggressive agitation to keep the seed pool fluid, it has been found that some of these after-market disks can increase the likelihood for the seed meter to overfill which can lead to meter performance problems or failures.
It has been determined that the potential for overfilling of the Pro-Series™ Meter when using seed disks designed to provide greater seed pool agitation, is partially attributed to the size and position of the opening within the seed meter housing through which the seed enters the seed reservoir from the auxiliary hopper. As will be explained in more detail later, when using larger or deeper ribs, more seeds are scooped up by the larger ribs which, due to the size and position of the opening, the void created by the seeds scooped up by the larger ribs is replenished with new seeds entering from the auxiliary hopper. Thus, in such circumstances, more seeds continually enter the seed reservoir than are actually being discharged out of the seed meter. As the seed disk rotates, the extra seeds carried by the larger ribs are returned to the seed pool which further adds to the seed pool that has already been replenished. Accordingly, over time, the meter can overfill.
Deere made an attempt to eliminate the tendency of the Pro-Series™ Meter to overfill by positioning a brush as a sort of lid to hold back or prevent the seed from rising above the seed reservoir. This brush lid is shown in U.S. Pat. No. 6,581,533 (see FIG. 4 of '533 patent at reference numeral 68). While Deere's approach was moderately successful, where more aggressive agitation on the disk is needed, the brush lid does not sufficiently prevent over filling. Additionally, the presence of the brush can have an adverse effect upon meter performance as some seed types and sizes of seeds are physically disturbed by the brush while the seeds are being loaded on the seed disk, thereby causing unwanted skips.
Accordingly, there is a need for a cost effective solution that will enable farmers to modify or retrofit their existing Pro-Series Meters to overcome the deficiencies described above while not having to replace the entire seed meter. Similarly, there is a need for a new design which can be adopted by original equipment manufacturers or after-market suppliers to overcome the deficiencies associated with the existing Pro-Series design with minimal retooling or changes to the seed meter and with minimal changes to the on-demand delivery system structure.